X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Fnetlink-socket.c;h=e4cc4ad62810cd5520ea1d3518c295b2ecd9f118;hb=HEAD;hp=15a800b456003d7091e51c1c27fc1390f0afa88c;hpb=407556ac6c902d060202f5e1aa3b92849b8f99ed;p=sliver-openvswitch.git diff --git a/lib/netlink-socket.c b/lib/netlink-socket.c index 15a800b45..e4cc4ad62 100644 --- a/lib/netlink-socket.c +++ b/lib/netlink-socket.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira Networks. + * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -16,7 +16,6 @@ #include #include "netlink-socket.h" -#include #include #include #include @@ -30,9 +29,10 @@ #include "netlink.h" #include "netlink-protocol.h" #include "ofpbuf.h" +#include "ovs-thread.h" #include "poll-loop.h" +#include "seq.h" #include "socket-util.h" -#include "stress.h" #include "util.h" #include "vlog.h" @@ -41,7 +41,6 @@ VLOG_DEFINE_THIS_MODULE(netlink_socket); COVERAGE_DEFINE(netlink_overflow); COVERAGE_DEFINE(netlink_received); COVERAGE_DEFINE(netlink_recv_jumbo); -COVERAGE_DEFINE(netlink_send); COVERAGE_DEFINE(netlink_sent); /* Linux header file confusion causes this to be undefined. */ @@ -54,17 +53,17 @@ COVERAGE_DEFINE(netlink_sent); * information. Also, at high logging levels we log *all* Netlink messages. */ static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(60, 600); +static uint32_t nl_sock_allocate_seq(struct nl_sock *, unsigned int n); static void log_nlmsg(const char *function, int error, const void *message, size_t size, int protocol); /* Netlink sockets. */ -struct nl_sock -{ +struct nl_sock { int fd; + uint32_t next_seq; uint32_t pid; int protocol; - struct nl_dump *dump; unsigned int rcvbuf; /* Receive buffer size (SO_RCVBUF). */ }; @@ -78,28 +77,30 @@ struct nl_sock * Initialized by nl_sock_create(). */ static int max_iovs; -static int nl_sock_cow__(struct nl_sock *); +static int nl_pool_alloc(int protocol, struct nl_sock **sockp); +static void nl_pool_release(struct nl_sock *); /* Creates a new netlink socket for the given netlink 'protocol' * (NETLINK_ROUTE, NETLINK_GENERIC, ...). Returns 0 and sets '*sockp' to the - * new socket if successful, otherwise returns a positive errno value. */ + * new socket if successful, otherwise returns a positive errno value. */ int nl_sock_create(int protocol, struct nl_sock **sockp) { + static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER; struct nl_sock *sock; struct sockaddr_nl local, remote; socklen_t local_size; int rcvbuf; int retval = 0; - if (!max_iovs) { + if (ovsthread_once_start(&once)) { int save_errno = errno; errno = 0; max_iovs = sysconf(_SC_UIO_MAXIOV); if (max_iovs < _XOPEN_IOV_MAX) { if (max_iovs == -1 && errno) { - VLOG_WARN("sysconf(_SC_UIO_MAXIOV): %s", strerror(errno)); + VLOG_WARN("sysconf(_SC_UIO_MAXIOV): %s", ovs_strerror(errno)); } max_iovs = _XOPEN_IOV_MAX; } else if (max_iovs > MAX_IOVS) { @@ -107,27 +108,29 @@ nl_sock_create(int protocol, struct nl_sock **sockp) } errno = save_errno; + ovsthread_once_done(&once); } *sockp = NULL; - sock = malloc(sizeof *sock); - if (sock == NULL) { - return ENOMEM; - } + sock = xmalloc(sizeof *sock); sock->fd = socket(AF_NETLINK, SOCK_RAW, protocol); if (sock->fd < 0) { - VLOG_ERR("fcntl: %s", strerror(errno)); + VLOG_ERR("fcntl: %s", ovs_strerror(errno)); goto error; } sock->protocol = protocol; - sock->dump = NULL; + sock->next_seq = 1; rcvbuf = 1024 * 1024; if (setsockopt(sock->fd, SOL_SOCKET, SO_RCVBUFFORCE, &rcvbuf, sizeof rcvbuf)) { - VLOG_WARN_RL(&rl, "setting %d-byte socket receive buffer failed (%s)", - rcvbuf, strerror(errno)); + /* Only root can use SO_RCVBUFFORCE. Everyone else gets EPERM. + * Warn only if the failure is therefore unexpected. */ + if (errno != EPERM) { + VLOG_WARN_RL(&rl, "setting %d-byte socket receive buffer failed " + "(%s)", rcvbuf, ovs_strerror(errno)); + } } retval = get_socket_rcvbuf(sock->fd); @@ -142,14 +145,14 @@ nl_sock_create(int protocol, struct nl_sock **sockp) remote.nl_family = AF_NETLINK; remote.nl_pid = 0; if (connect(sock->fd, (struct sockaddr *) &remote, sizeof remote) < 0) { - VLOG_ERR("connect(0): %s", strerror(errno)); + VLOG_ERR("connect(0): %s", ovs_strerror(errno)); goto error; } /* Obtain pid assigned by kernel. */ local_size = sizeof local; if (getsockname(sock->fd, (struct sockaddr *) &local, &local_size) < 0) { - VLOG_ERR("getsockname: %s", strerror(errno)); + VLOG_ERR("getsockname: %s", ovs_strerror(errno)); goto error; } if (local_size < sizeof local || local.nl_family != AF_NETLINK) { @@ -190,12 +193,8 @@ void nl_sock_destroy(struct nl_sock *sock) { if (sock) { - if (sock->dump) { - sock->dump = NULL; - } else { - close(sock->fd); - free(sock); - } + close(sock->fd); + free(sock); } } @@ -213,14 +212,10 @@ nl_sock_destroy(struct nl_sock *sock) int nl_sock_join_mcgroup(struct nl_sock *sock, unsigned int multicast_group) { - int error = nl_sock_cow__(sock); - if (error) { - return error; - } if (setsockopt(sock->fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &multicast_group, sizeof multicast_group) < 0) { VLOG_WARN("could not join multicast group %u (%s)", - multicast_group, strerror(errno)); + multicast_group, ovs_strerror(errno)); return errno; } return 0; @@ -239,30 +234,31 @@ nl_sock_join_mcgroup(struct nl_sock *sock, unsigned int multicast_group) int nl_sock_leave_mcgroup(struct nl_sock *sock, unsigned int multicast_group) { - assert(!sock->dump); if (setsockopt(sock->fd, SOL_NETLINK, NETLINK_DROP_MEMBERSHIP, &multicast_group, sizeof multicast_group) < 0) { VLOG_WARN("could not leave multicast group %u (%s)", - multicast_group, strerror(errno)); + multicast_group, ovs_strerror(errno)); return errno; } return 0; } static int -nl_sock_send__(struct nl_sock *sock, const struct ofpbuf *msg, bool wait) +nl_sock_send__(struct nl_sock *sock, const struct ofpbuf *msg, + uint32_t nlmsg_seq, bool wait) { struct nlmsghdr *nlmsg = nl_msg_nlmsghdr(msg); int error; - nlmsg->nlmsg_len = msg->size; + nlmsg->nlmsg_len = ofpbuf_size(msg); + nlmsg->nlmsg_seq = nlmsg_seq; nlmsg->nlmsg_pid = sock->pid; do { int retval; - retval = send(sock->fd, msg->data, msg->size, wait ? 0 : MSG_DONTWAIT); + retval = send(sock->fd, ofpbuf_data(msg), ofpbuf_size(msg), wait ? 0 : MSG_DONTWAIT); error = retval < 0 ? errno : 0; } while (error == EINTR); - log_nlmsg(__func__, error, msg->data, msg->size, sock->protocol); + log_nlmsg(__func__, error, ofpbuf_data(msg), ofpbuf_size(msg), sock->protocol); if (!error) { COVERAGE_INC(netlink_sent); } @@ -270,8 +266,9 @@ nl_sock_send__(struct nl_sock *sock, const struct ofpbuf *msg, bool wait) } /* Tries to send 'msg', which must contain a Netlink message, to the kernel on - * 'sock'. nlmsg_len in 'msg' will be finalized to match msg->size, and - * nlmsg_pid will be set to 'sock''s pid, before the message is sent. + * 'sock'. nlmsg_len in 'msg' will be finalized to match ofpbuf_size(msg), nlmsg_pid + * will be set to 'sock''s pid, and nlmsg_seq will be initialized to a fresh + * sequence number, before the message is sent. * * Returns 0 if successful, otherwise a positive errno value. If * 'wait' is true, then the send will wait until buffer space is ready; @@ -279,49 +276,48 @@ nl_sock_send__(struct nl_sock *sock, const struct ofpbuf *msg, bool wait) int nl_sock_send(struct nl_sock *sock, const struct ofpbuf *msg, bool wait) { - int error = nl_sock_cow__(sock); - if (error) { - return error; - } - return nl_sock_send__(sock, msg, wait); + return nl_sock_send_seq(sock, msg, nl_sock_allocate_seq(sock, 1), wait); } -/* This stress option is useful for testing that OVS properly tolerates - * -ENOBUFS on NetLink sockets. Such errors are unavoidable because they can - * occur if the kernel cannot temporarily allocate enough GFP_ATOMIC memory to - * reply to a request. They can also occur if messages arrive on a multicast - * channel faster than OVS can process them. */ -STRESS_OPTION( - netlink_overflow, "simulate netlink socket receive buffer overflow", - 5, 1, -1, 100); +/* Tries to send 'msg', which must contain a Netlink message, to the kernel on + * 'sock'. nlmsg_len in 'msg' will be finalized to match ofpbuf_size(msg), nlmsg_pid + * will be set to 'sock''s pid, and nlmsg_seq will be initialized to + * 'nlmsg_seq', before the message is sent. + * + * Returns 0 if successful, otherwise a positive errno value. If + * 'wait' is true, then the send will wait until buffer space is ready; + * otherwise, returns EAGAIN if the 'sock' send buffer is full. + * + * This function is suitable for sending a reply to a request that was received + * with sequence number 'nlmsg_seq'. Otherwise, use nl_sock_send() instead. */ +int +nl_sock_send_seq(struct nl_sock *sock, const struct ofpbuf *msg, + uint32_t nlmsg_seq, bool wait) +{ + return nl_sock_send__(sock, msg, nlmsg_seq, wait); +} static int -nl_sock_recv__(struct nl_sock *sock, struct ofpbuf **bufp, bool wait) +nl_sock_recv__(struct nl_sock *sock, struct ofpbuf *buf, bool wait) { - /* We can't accurately predict the size of the data to be received. Most - * received data will fit in a 2 kB buffer, so we allocate that much space. - * In case the data is actually bigger than that, we make available enough - * additional space to allow Netlink messages to be up to 64 kB long (a - * reasonable figure since that's the maximum length of a Netlink - * attribute). */ - enum { MAX_SIZE = 65536 }; - enum { HEAD_SIZE = 2048 }; - enum { TAIL_SIZE = MAX_SIZE - HEAD_SIZE }; - + /* We can't accurately predict the size of the data to be received. The + * caller is supposed to have allocated enough space in 'buf' to handle the + * "typical" case. To handle exceptions, we make available enough space in + * 'tail' to allow Netlink messages to be up to 64 kB long (a reasonable + * figure since that's the maximum length of a Netlink attribute). */ struct nlmsghdr *nlmsghdr; - uint8_t tail[TAIL_SIZE]; + uint8_t tail[65536]; struct iovec iov[2]; - struct ofpbuf *buf; struct msghdr msg; ssize_t retval; - *bufp = NULL; + ovs_assert(buf->allocated >= sizeof *nlmsghdr); + ofpbuf_clear(buf); - buf = ofpbuf_new(HEAD_SIZE); - iov[0].iov_base = buf->data; - iov[0].iov_len = HEAD_SIZE; + iov[0].iov_base = ofpbuf_base(buf); + iov[0].iov_len = buf->allocated; iov[1].iov_base = tail; - iov[1].iov_len = TAIL_SIZE; + iov[1].iov_len = sizeof tail; memset(&msg, 0, sizeof msg); msg.msg_iov = iov; @@ -338,77 +334,57 @@ nl_sock_recv__(struct nl_sock *sock, struct ofpbuf **bufp, bool wait) * the kernel tried to send to us. */ COVERAGE_INC(netlink_overflow); } - ofpbuf_delete(buf); return error; } if (msg.msg_flags & MSG_TRUNC) { - VLOG_ERR_RL(&rl, "truncated message (longer than %d bytes)", MAX_SIZE); - ofpbuf_delete(buf); + VLOG_ERR_RL(&rl, "truncated message (longer than %"PRIuSIZE" bytes)", + sizeof tail); return E2BIG; } - ofpbuf_put_uninit(buf, MIN(retval, HEAD_SIZE)); - if (retval > HEAD_SIZE) { - COVERAGE_INC(netlink_recv_jumbo); - ofpbuf_put(buf, tail, retval - HEAD_SIZE); - } - - nlmsghdr = buf->data; + nlmsghdr = ofpbuf_data(buf); if (retval < sizeof *nlmsghdr || nlmsghdr->nlmsg_len < sizeof *nlmsghdr || nlmsghdr->nlmsg_len > retval) { - VLOG_ERR_RL(&rl, "received invalid nlmsg (%zd bytes < %d)", - retval, NLMSG_HDRLEN); - ofpbuf_delete(buf); + VLOG_ERR_RL(&rl, "received invalid nlmsg (%"PRIuSIZE"d bytes < %"PRIuSIZE")", + retval, sizeof *nlmsghdr); return EPROTO; } - if (STRESS(netlink_overflow)) { - ofpbuf_delete(buf); - return ENOBUFS; + ofpbuf_set_size(buf, MIN(retval, buf->allocated)); + if (retval > buf->allocated) { + COVERAGE_INC(netlink_recv_jumbo); + ofpbuf_put(buf, tail, retval - buf->allocated); } - *bufp = buf; - log_nlmsg(__func__, 0, buf->data, buf->size, sock->protocol); + log_nlmsg(__func__, 0, ofpbuf_data(buf), ofpbuf_size(buf), sock->protocol); COVERAGE_INC(netlink_received); return 0; } -/* Tries to receive a netlink message from the kernel on 'sock'. If - * successful, stores the received message into '*bufp' and returns 0. The - * caller is responsible for destroying the message with ofpbuf_delete(). On - * failure, returns a positive errno value and stores a null pointer into - * '*bufp'. +/* Tries to receive a Netlink message from the kernel on 'sock' into 'buf'. If + * 'wait' is true, waits for a message to be ready. Otherwise, fails with + * EAGAIN if the 'sock' receive buffer is empty. + * + * The caller must have initialized 'buf' with an allocation of at least + * NLMSG_HDRLEN bytes. For best performance, the caller should allocate enough + * space for a "typical" message. + * + * On success, returns 0 and replaces 'buf''s previous content by the received + * message. This function expands 'buf''s allocated memory, as necessary, to + * hold the actual size of the received message. * - * If 'wait' is true, nl_sock_recv waits for a message to be ready; otherwise, - * returns EAGAIN if the 'sock' receive buffer is empty. */ + * On failure, returns a positive errno value and clears 'buf' to zero length. + * 'buf' retains its previous memory allocation. + * + * Regardless of success or failure, this function resets 'buf''s headroom to + * 0. */ int -nl_sock_recv(struct nl_sock *sock, struct ofpbuf **bufp, bool wait) -{ - int error = nl_sock_cow__(sock); - if (error) { - return error; - } - return nl_sock_recv__(sock, bufp, wait); -} - -static int -find_nl_transaction_by_seq(struct nl_transaction **transactions, size_t n, - uint32_t seq) +nl_sock_recv(struct nl_sock *sock, struct ofpbuf *buf, bool wait) { - int i; - - for (i = 0; i < n; i++) { - struct nl_transaction *t = transactions[i]; - - if (seq == nl_msg_nlmsghdr(t->request)->nlmsg_seq) { - return i; - } - } - - return -1; + return nl_sock_recv__(sock, buf, wait); } static void @@ -418,8 +394,12 @@ nl_sock_record_errors__(struct nl_transaction **transactions, size_t n, size_t i; for (i = 0; i < n; i++) { - transactions[i]->error = error; - transactions[i]->reply = NULL; + struct nl_transaction *txn = transactions[i]; + + txn->error = error; + if (txn->reply) { + ofpbuf_clear(txn->reply); + } } } @@ -428,21 +408,28 @@ nl_sock_transact_multiple__(struct nl_sock *sock, struct nl_transaction **transactions, size_t n, size_t *done) { + uint64_t tmp_reply_stub[1024 / 8]; + struct nl_transaction tmp_txn; + struct ofpbuf tmp_reply; + + uint32_t base_seq; struct iovec iovs[MAX_IOVS]; struct msghdr msg; int error; int i; + base_seq = nl_sock_allocate_seq(sock, n); *done = 0; for (i = 0; i < n; i++) { - struct ofpbuf *request = transactions[i]->request; - struct nlmsghdr *nlmsg = nl_msg_nlmsghdr(request); + struct nl_transaction *txn = transactions[i]; + struct nlmsghdr *nlmsg = nl_msg_nlmsghdr(txn->request); - nlmsg->nlmsg_len = request->size; + nlmsg->nlmsg_len = ofpbuf_size(txn->request); + nlmsg->nlmsg_seq = base_seq + i; nlmsg->nlmsg_pid = sock->pid; - iovs[i].iov_base = request->data; - iovs[i].iov_len = request->size; + iovs[i].iov_base = ofpbuf_data(txn->request); + iovs[i].iov_len = ofpbuf_size(txn->request); } memset(&msg, 0, sizeof msg); @@ -453,9 +440,9 @@ nl_sock_transact_multiple__(struct nl_sock *sock, } while (error == EINTR); for (i = 0; i < n; i++) { - struct ofpbuf *request = transactions[i]->request; + struct nl_transaction *txn = transactions[i]; - log_nlmsg(__func__, error, request->data, request->size, + log_nlmsg(__func__, error, ofpbuf_data(txn->request), ofpbuf_size(txn->request), sock->protocol); } if (!error) { @@ -466,63 +453,93 @@ nl_sock_transact_multiple__(struct nl_sock *sock, return error; } + ofpbuf_use_stub(&tmp_reply, tmp_reply_stub, sizeof tmp_reply_stub); + tmp_txn.request = NULL; + tmp_txn.reply = &tmp_reply; + tmp_txn.error = 0; while (n > 0) { - struct ofpbuf *reply; + struct nl_transaction *buf_txn, *txn; + uint32_t seq; + + /* Find a transaction whose buffer we can use for receiving a reply. + * If no such transaction is left, use tmp_txn. */ + buf_txn = &tmp_txn; + for (i = 0; i < n; i++) { + if (transactions[i]->reply) { + buf_txn = transactions[i]; + break; + } + } - error = nl_sock_recv__(sock, &reply, false); - if (error == EAGAIN) { - nl_sock_record_errors__(transactions, n, 0); - *done += n; - return 0; - } else if (error) { - return error; + /* Receive a reply. */ + error = nl_sock_recv__(sock, buf_txn->reply, false); + if (error) { + if (error == EAGAIN) { + nl_sock_record_errors__(transactions, n, 0); + *done += n; + error = 0; + } + break; } - i = find_nl_transaction_by_seq(transactions, n, - nl_msg_nlmsghdr(reply)->nlmsg_seq); - if (i < 0) { - VLOG_DBG_RL(&rl, "ignoring unexpected seq %#"PRIx32, - nl_msg_nlmsghdr(reply)->nlmsg_seq); - ofpbuf_delete(reply); + /* Match the reply up with a transaction. */ + seq = nl_msg_nlmsghdr(buf_txn->reply)->nlmsg_seq; + if (seq < base_seq || seq >= base_seq + n) { + VLOG_DBG_RL(&rl, "ignoring unexpected seq %#"PRIx32, seq); continue; } + i = seq - base_seq; + txn = transactions[i]; - nl_sock_record_errors__(transactions, i, 0); - if (nl_msg_nlmsgerr(reply, &error)) { - transactions[i]->reply = NULL; - transactions[i]->error = error; - if (error) { + /* Fill in the results for 'txn'. */ + if (nl_msg_nlmsgerr(buf_txn->reply, &txn->error)) { + if (txn->reply) { + ofpbuf_clear(txn->reply); + } + if (txn->error) { VLOG_DBG_RL(&rl, "received NAK error=%d (%s)", - error, strerror(error)); + error, ovs_strerror(txn->error)); } - ofpbuf_delete(reply); } else { - transactions[i]->reply = reply; - transactions[i]->error = 0; + txn->error = 0; + if (txn->reply && txn != buf_txn) { + /* Swap buffers. */ + struct ofpbuf *reply = buf_txn->reply; + buf_txn->reply = txn->reply; + txn->reply = reply; + } } + /* Fill in the results for transactions before 'txn'. (We have to do + * this after the results for 'txn' itself because of the buffer swap + * above.) */ + nl_sock_record_errors__(transactions, i, 0); + + /* Advance. */ *done += i + 1; transactions += i + 1; n -= i + 1; + base_seq += i + 1; } + ofpbuf_uninit(&tmp_reply); - return 0; + return error; } -/* Sends the 'request' member of the 'n' transactions in 'transactions' to the - * kernel, in order, and waits for responses to all of them. Fills in the +/* Sends the 'request' member of the 'n' transactions in 'transactions' on + * 'sock', in order, and receives responses to all of them. Fills in the * 'error' member of each transaction with 0 if it was successful, otherwise - * with a positive errno value. 'reply' will be NULL on error or if the - * transaction was successful but had no reply beyond an indication of success. - * For a successful transaction that did have a more detailed reply, 'reply' - * will be set to the reply message. + * with a positive errno value. If 'reply' is nonnull, then it will be filled + * with the reply if the message receives a detailed reply. In other cases, + * i.e. where the request failed or had no reply beyond an indication of + * success, 'reply' will be cleared if it is nonnull. * * The caller is responsible for destroying each request and reply, and the * transactions array itself. * * Before sending each message, this function will finalize nlmsg_len in each - * 'request' to match the ofpbuf's size, and set nlmsg_pid to 'sock''s pid. - * NLM_F_ACK will be added to some requests' nlmsg_flags. + * 'request' to match the ofpbuf's size, set nlmsg_pid to 'sock''s pid, and + * initialize nlmsg_seq. * * Bare Netlink is an unreliable transport protocol. This function layers * reliable delivery and reply semantics on top of bare Netlink. See @@ -539,12 +556,6 @@ nl_sock_transact_multiple(struct nl_sock *sock, return; } - error = nl_sock_cow__(sock); - if (error) { - nl_sock_record_errors__(transactions, n, error); - return; - } - /* In theory, every request could have a 64 kB reply. But the default and * maximum socket rcvbuf size with typical Dom0 memory sizes both tend to * be a bit below 128 kB, so that would only allow a single message in a @@ -568,12 +579,12 @@ nl_sock_transact_multiple(struct nl_sock *sock, #else enum { MAX_BATCH_BYTES = 4096 - 512 }; #endif - bytes = transactions[0]->request->size; + bytes = ofpbuf_size(transactions[0]->request); for (count = 1; count < n && count < max_batch_count; count++) { - if (bytes + transactions[count]->request->size > MAX_BATCH_BYTES) { + if (bytes + ofpbuf_size(transactions[count]->request) > MAX_BATCH_BYTES) { break; } - bytes += transactions[count]->request->size; + bytes += ofpbuf_size(transactions[count]->request); } error = nl_sock_transact_multiple__(sock, transactions, count, &done); @@ -583,7 +594,7 @@ nl_sock_transact_multiple(struct nl_sock *sock, if (error == ENOBUFS) { VLOG_DBG_RL(&rl, "receive buffer overflow, resending request"); } else if (error) { - VLOG_ERR_RL(&rl, "transaction error (%s)", strerror(error)); + VLOG_ERR_RL(&rl, "transaction error (%s)", ovs_strerror(error)); nl_sock_record_errors__(transactions, n, error); } } @@ -597,9 +608,9 @@ nl_sock_transact_multiple(struct nl_sock *sock, * on failure '*replyp' is set to NULL. If 'replyp' is null, then the kernel's * reply, if any, is discarded. * - * nlmsg_len in 'msg' will be finalized to match msg->size, and nlmsg_pid will - * be set to 'sock''s pid, before the message is sent. NLM_F_ACK will be set - * in nlmsg_flags. + * Before the message is sent, nlmsg_len in 'request' will be finalized to + * match ofpbuf_size(msg), nlmsg_pid will be set to 'sock''s pid, and nlmsg_seq will + * be initialized, NLM_F_ACK will be set in nlmsg_flags. * * The caller is responsible for destroying 'request'. * @@ -636,14 +647,21 @@ nl_sock_transact(struct nl_sock *sock, const struct ofpbuf *request, struct nl_transaction *transactionp; struct nl_transaction transaction; - transaction.request = (struct ofpbuf *) request; + transaction.request = CONST_CAST(struct ofpbuf *, request); + transaction.reply = replyp ? ofpbuf_new(1024) : NULL; transactionp = &transaction; + nl_sock_transact_multiple(sock, &transactionp, 1); + if (replyp) { - *replyp = transaction.reply; - } else { - ofpbuf_delete(transaction.reply); + if (transaction.error) { + ofpbuf_delete(transaction.reply); + *replyp = NULL; + } else { + *replyp = transaction.reply; + } } + return transaction.error; } @@ -651,175 +669,132 @@ nl_sock_transact(struct nl_sock *sock, const struct ofpbuf *request, int nl_sock_drain(struct nl_sock *sock) { - int error = nl_sock_cow__(sock); - if (error) { - return error; - } return drain_rcvbuf(sock->fd); } -/* The client is attempting some operation on 'sock'. If 'sock' has an ongoing - * dump operation, then replace 'sock''s fd with a new socket and hand 'sock''s - * old fd over to the dump. */ -static int -nl_sock_cow__(struct nl_sock *sock) -{ - struct nl_sock *copy; - uint32_t tmp_pid; - int tmp_fd; - int error; - - if (!sock->dump) { - return 0; - } - - error = nl_sock_clone(sock, ©); - if (error) { - return error; - } - - tmp_fd = sock->fd; - sock->fd = copy->fd; - copy->fd = tmp_fd; - - tmp_pid = sock->pid; - sock->pid = copy->pid; - copy->pid = tmp_pid; - - sock->dump->sock = copy; - sock->dump = NULL; - - return 0; -} - -/* Starts a Netlink "dump" operation, by sending 'request' to the kernel via - * 'sock', and initializes 'dump' to reflect the state of the operation. +/* Starts a Netlink "dump" operation, by sending 'request' to the kernel on a + * Netlink socket created with the given 'protocol', and initializes 'dump' to + * reflect the state of the operation. * - * nlmsg_len in 'msg' will be finalized to match msg->size, and nlmsg_pid will - * be set to 'sock''s pid, before the message is sent. NLM_F_DUMP and - * NLM_F_ACK will be set in nlmsg_flags. + * 'request' must contain a Netlink message. Before sending the message, + * nlmsg_len will be finalized to match request->size, and nlmsg_pid will be + * set to the Netlink socket's pid. NLM_F_DUMP and NLM_F_ACK will be set in + * nlmsg_flags. * - * This Netlink socket library is designed to ensure that the dump is reliable - * and that it will not interfere with other operations on 'sock', including - * destroying or sending and receiving messages on 'sock'. One corner case is - * not handled: + * The design of this Netlink socket library ensures that the dump is reliable. * - * - If 'sock' has been used to send a request (e.g. with nl_sock_send()) - * whose response has not yet been received (e.g. with nl_sock_recv()). - * This is unusual: usually nl_sock_transact() is used to send a message - * and receive its reply all in one go. + * This function provides no status indication. nl_dump_done() provides an + * error status for the entire dump operation. * - * This function provides no status indication. An error status for the entire - * dump operation is provided when it is completed by calling nl_dump_done(). - * - * The caller is responsible for destroying 'request'. - * - * The new 'dump' is independent of 'sock'. 'sock' and 'dump' may be destroyed - * in either order. + * The caller must eventually destroy 'request'. */ void -nl_dump_start(struct nl_dump *dump, - struct nl_sock *sock, const struct ofpbuf *request) -{ - struct nlmsghdr *nlmsghdr = nl_msg_nlmsghdr(request); - nlmsghdr->nlmsg_flags |= NLM_F_DUMP | NLM_F_ACK; - dump->seq = nlmsghdr->nlmsg_seq; - dump->buffer = NULL; - if (sock->dump) { - /* 'sock' already has an ongoing dump. Clone the socket because - * Netlink only allows one dump at a time. */ - dump->status = nl_sock_clone(sock, &dump->sock); - if (dump->status) { - return; - } - } else { - sock->dump = dump; - dump->sock = sock; - dump->status = 0; - } - dump->status = nl_sock_send__(sock, request, true); -} - -/* Helper function for nl_dump_next(). */ -static int -nl_dump_recv(struct nl_dump *dump, struct ofpbuf **bufferp) +nl_dump_start(struct nl_dump *dump, int protocol, const struct ofpbuf *request) { - struct nlmsghdr *nlmsghdr; - struct ofpbuf *buffer; - int retval; - - retval = nl_sock_recv__(dump->sock, bufferp, true); - if (retval) { - return retval == EINTR ? EAGAIN : retval; - } - buffer = *bufferp; + int status = nl_pool_alloc(protocol, &dump->sock); - nlmsghdr = nl_msg_nlmsghdr(buffer); - if (dump->seq != nlmsghdr->nlmsg_seq) { - VLOG_DBG_RL(&rl, "ignoring seq %#"PRIx32" != expected %#"PRIx32, - nlmsghdr->nlmsg_seq, dump->seq); - return EAGAIN; - } - - if (nl_msg_nlmsgerr(buffer, &retval)) { - VLOG_INFO_RL(&rl, "netlink dump request error (%s)", - strerror(retval)); - return retval && retval != EAGAIN ? retval : EPROTO; + if (status) { + return; } - return 0; + nl_msg_nlmsghdr(request)->nlmsg_flags |= NLM_F_DUMP | NLM_F_ACK; + status = nl_sock_send__(dump->sock, request, + nl_sock_allocate_seq(dump->sock, 1), true); + atomic_init(&dump->status, status << 1); + dump->nl_seq = nl_msg_nlmsghdr(request)->nlmsg_seq; + dump->status_seq = seq_create(); } -/* Attempts to retrieve another reply from 'dump', which must have been - * initialized with nl_dump_start(). +/* Attempts to retrieve another reply from 'dump' into 'buffer'. 'dump' must + * have been initialized with nl_dump_start(), and 'buffer' must have been + * initialized. 'buffer' should be at least NL_DUMP_BUFSIZE bytes long. * - * If successful, returns true and points 'reply->data' and 'reply->size' to - * the message that was retrieved. The caller must not modify 'reply' (because - * it points into the middle of a larger buffer). + * If successful, returns true and points 'reply->data' and 'ofpbuf_size(reply)' to + * the message that was retrieved. The caller must not modify 'reply' (because + * it points within 'buffer', which will be used by future calls to this + * function). * - * On failure, returns false and sets 'reply->data' to NULL and 'reply->size' + * On failure, returns false and sets 'reply->data' to NULL and 'ofpbuf_size(reply)' * to 0. Failure might indicate an actual error or merely the end of replies. * An error status for the entire dump operation is provided when it is * completed by calling nl_dump_done(). + * + * Multiple threads may call this function, passing the same nl_dump, however + * each must provide independent buffers. This function may cache multiple + * replies in the buffer, and these will be processed before more replies are + * fetched. When this function returns false, other threads may continue to + * process replies in their buffers, but they will not fetch more replies. */ bool -nl_dump_next(struct nl_dump *dump, struct ofpbuf *reply) +nl_dump_next(struct nl_dump *dump, struct ofpbuf *reply, struct ofpbuf *buffer) { struct nlmsghdr *nlmsghdr; + int error = 0; - reply->data = NULL; - reply->size = 0; - if (dump->status) { - return false; - } + ofpbuf_set_data(reply, NULL); + ofpbuf_set_size(reply, 0); - if (dump->buffer && !dump->buffer->size) { - ofpbuf_delete(dump->buffer); - dump->buffer = NULL; - } - while (!dump->buffer) { - int retval = nl_dump_recv(dump, &dump->buffer); + /* If 'buffer' is empty, fetch another batch of nlmsgs. */ + while (!ofpbuf_size(buffer)) { + unsigned int status; + int retval, seq; + + seq = seq_read(dump->status_seq); + atomic_read(&dump->status, &status); + if (status) { + return false; + } + + retval = nl_sock_recv__(dump->sock, buffer, false); if (retval) { - ofpbuf_delete(dump->buffer); - dump->buffer = NULL; - if (retval != EAGAIN) { - dump->status = retval; - return false; + ofpbuf_clear(buffer); + if (retval == EAGAIN) { + nl_sock_wait(dump->sock, POLLIN); + seq_wait(dump->status_seq, seq); + poll_block(); + continue; + } else { + error = retval; + goto exit; } } + + nlmsghdr = nl_msg_nlmsghdr(buffer); + if (dump->nl_seq != nlmsghdr->nlmsg_seq) { + VLOG_DBG_RL(&rl, "ignoring seq %#"PRIx32" != expected %#"PRIx32, + nlmsghdr->nlmsg_seq, dump->nl_seq); + ofpbuf_clear(buffer); + continue; + } + + if (nl_msg_nlmsgerr(buffer, &retval) && retval) { + VLOG_INFO_RL(&rl, "netlink dump request error (%s)", + ovs_strerror(retval)); + error = retval == EAGAIN ? EPROTO : retval; + ofpbuf_clear(buffer); + goto exit; + } } - nlmsghdr = nl_msg_next(dump->buffer, reply); + /* Fetch the next nlmsg in the current batch. */ + nlmsghdr = nl_msg_next(buffer, reply); if (!nlmsghdr) { VLOG_WARN_RL(&rl, "netlink dump reply contains message fragment"); - dump->status = EPROTO; - return false; + error = EPROTO; } else if (nlmsghdr->nlmsg_type == NLMSG_DONE) { - dump->status = EOF; - return false; + error = EOF; } - return true; +exit: + if (error == EOF) { + unsigned int old; + atomic_or(&dump->status, 1, &old); + seq_change(dump->status_seq); + } else if (error) { + atomic_store(&dump->status, error << 1); + seq_change(dump->status_seq); + } + return !error; } /* Completes Netlink dump operation 'dump', which must have been initialized @@ -828,24 +803,28 @@ nl_dump_next(struct nl_dump *dump, struct ofpbuf *reply) int nl_dump_done(struct nl_dump *dump) { - /* Drain any remaining messages that the client didn't read. Otherwise the - * kernel will continue to queue them up and waste buffer space. */ - while (!dump->status) { - struct ofpbuf reply; - if (!nl_dump_next(dump, &reply)) { - assert(dump->status); - } - } + int status; - if (dump->sock) { - if (dump->sock->dump) { - dump->sock->dump = NULL; - } else { - nl_sock_destroy(dump->sock); + /* Drain any remaining messages that the client didn't read. Otherwise the + * kernel will continue to queue them up and waste buffer space. + * + * XXX We could just destroy and discard the socket in this case. */ + atomic_read(&dump->status, &status); + if (!status) { + uint64_t tmp_reply_stub[NL_DUMP_BUFSIZE / 8]; + struct ofpbuf reply, buf; + + ofpbuf_use_stub(&buf, tmp_reply_stub, sizeof tmp_reply_stub); + while (nl_dump_next(dump, &reply, &buf)) { + /* Nothing to do. */ } + atomic_read(&dump->status, &status); + ovs_assert(status); + ofpbuf_uninit(&buf); } - ofpbuf_delete(dump->buffer); - return dump->status == EOF ? 0 : dump->status; + nl_pool_release(dump->sock); + seq_destroy(dump->status_seq); + return status >> 1; } /* Causes poll_block() to wake up when any of the specified 'events' (which is @@ -975,12 +954,10 @@ do_lookup_genl_family(const char *name, struct nlattr **attrs, /* Finds the multicast group called 'group_name' in genl family 'family_name'. * When successful, writes its result to 'multicast_group' and returns 0. * Otherwise, clears 'multicast_group' and returns a positive error code. - * - * Some kernels do not support looking up a multicast group with this function. - * In this case, 'multicast_group' will be populated with 'fallback'. */ + */ int nl_lookup_genl_mcgroup(const char *family_name, const char *group_name, - unsigned int *multicast_group, unsigned int fallback) + unsigned int *multicast_group) { struct nlattr *family_attrs[ARRAY_SIZE(family_policy)]; const struct nlattr *mc; @@ -995,10 +972,7 @@ nl_lookup_genl_mcgroup(const char *family_name, const char *group_name, } if (!family_attrs[CTRL_ATTR_MCAST_GROUPS]) { - *multicast_group = fallback; - VLOG_WARN("%s-%s: has no multicast group, using fallback %d", - family_name, group_name, *multicast_group); - error = 0; + error = EPROTO; goto exit; } @@ -1052,11 +1026,112 @@ nl_lookup_genl_family(const char *name, int *number) } ofpbuf_delete(reply); - assert(*number != 0); + ovs_assert(*number != 0); } return *number > 0 ? 0 : -*number; } +struct nl_pool { + struct nl_sock *socks[16]; + int n; +}; + +static struct ovs_mutex pool_mutex = OVS_MUTEX_INITIALIZER; +static struct nl_pool pools[MAX_LINKS] OVS_GUARDED_BY(pool_mutex); + +static int +nl_pool_alloc(int protocol, struct nl_sock **sockp) +{ + struct nl_sock *sock = NULL; + struct nl_pool *pool; + + ovs_assert(protocol >= 0 && protocol < ARRAY_SIZE(pools)); + + ovs_mutex_lock(&pool_mutex); + pool = &pools[protocol]; + if (pool->n > 0) { + sock = pool->socks[--pool->n]; + } + ovs_mutex_unlock(&pool_mutex); + + if (sock) { + *sockp = sock; + return 0; + } else { + return nl_sock_create(protocol, sockp); + } +} + +static void +nl_pool_release(struct nl_sock *sock) +{ + if (sock) { + struct nl_pool *pool = &pools[sock->protocol]; + + ovs_mutex_lock(&pool_mutex); + if (pool->n < ARRAY_SIZE(pool->socks)) { + pool->socks[pool->n++] = sock; + sock = NULL; + } + ovs_mutex_unlock(&pool_mutex); + + nl_sock_destroy(sock); + } +} + +int +nl_transact(int protocol, const struct ofpbuf *request, + struct ofpbuf **replyp) +{ + struct nl_sock *sock; + int error; + + error = nl_pool_alloc(protocol, &sock); + if (error) { + *replyp = NULL; + return error; + } + + error = nl_sock_transact(sock, request, replyp); + + nl_pool_release(sock); + return error; +} + +void +nl_transact_multiple(int protocol, + struct nl_transaction **transactions, size_t n) +{ + struct nl_sock *sock; + int error; + + error = nl_pool_alloc(protocol, &sock); + if (!error) { + nl_sock_transact_multiple(sock, transactions, n); + nl_pool_release(sock); + } else { + nl_sock_record_errors__(transactions, n, error); + } +} + + +static uint32_t +nl_sock_allocate_seq(struct nl_sock *sock, unsigned int n) +{ + uint32_t seq = sock->next_seq; + + sock->next_seq += n; + + /* Make it impossible for the next request for sequence numbers to wrap + * around to 0. Start over with 1 to avoid ever using a sequence number of + * 0, because the kernel uses sequence number 0 for notifications. */ + if (sock->next_seq >= UINT32_MAX / 2) { + sock->next_seq = 1; + } + + return seq; +} + static void nlmsghdr_to_string(const struct nlmsghdr *h, int protocol, struct ds *ds) { @@ -1123,7 +1198,7 @@ nlmsg_to_string(const struct ofpbuf *buffer, int protocol) if (e) { ds_put_format(&ds, " error(%d", e->error); if (e->error < 0) { - ds_put_format(&ds, "(%s)", strerror(-e->error)); + ds_put_format(&ds, "(%s)", ovs_strerror(-e->error)); } ds_put_cstr(&ds, ", in-reply-to("); nlmsghdr_to_string(&e->msg, protocol, &ds); @@ -1136,7 +1211,7 @@ nlmsg_to_string(const struct ofpbuf *buffer, int protocol) if (error) { ds_put_format(&ds, " done(%d", *error); if (*error < 0) { - ds_put_format(&ds, "(%s)", strerror(-*error)); + ds_put_format(&ds, "(%s)", ovs_strerror(-*error)); } ds_put_cstr(&ds, ")"); } else { @@ -1168,8 +1243,6 @@ log_nlmsg(const char *function, int error, ofpbuf_use_const(&buffer, message, size); nlmsg = nlmsg_to_string(&buffer, protocol); - VLOG_DBG_RL(&rl, "%s (%s): %s", function, strerror(error), nlmsg); + VLOG_DBG_RL(&rl, "%s (%s): %s", function, ovs_strerror(error), nlmsg); free(nlmsg); } - -